1. Field of the Invention
This invention relates generally to harvesting machines and more particularly to a harvesting machine for harvesting plant life from the bottom of bodies of fresh water such as lakes and rivers.
2. Description of Problem
Eurasian Watermilfoil (myriophyllum spicatum) was accidentally introduced into North America from Europe in the 1940s. It most likely entered waters in eastern North America when aquarium owners released the contents of their aquariums into local lakes. It flourished there and began spreading westward by clinging to recreational boats. It is now present in waters across North America. Watermilfoil's explosive growth has choked many bodies of water, crowding out native plants and fish. It also tends to spoil them for boating and other water sports activities. This plant spreads naturally through stem fragments and underground runners. Fragments transported to new areas by watercraft or on waves and currents help to spread the growth. It continues to be a problem in lakes, ponds, and streams throughout the United States and Canada.
3. Description of Related Art
The following art defines the present state of this field and each disclosure is hereby incorporated herein by reference:
Hawk, U.S. Pat. No. 4,696,149 discloses a method for removal of aquatic weeds by first dragging the bottom of a lake with a horizontal bar to loosen the weeds from the bottom. The uprooted and broken weed stalks are permitted to float to the surface of the lake. The weeds are scooped from the water by a mesh scoop capable of being carried to a dumping area and emptied. The method is carried out by a self-propelled hull having a boom pivotally attached to a forward end thereof. The boom is adapted to receive various implements on its free end. One such implement is a horizontal drag bar with downwardly depending tines to drag the lake bottom and another of the implements is the wire mesh scoop mentioned above. The tines of the first implement each preferably include at least a portion that is angled forwardly, so that when the boom is lowered sufficiently to meet the lake bottom the angled portion of the tine if substantially orthogonal to the lake bottom. The tines preferably are at least partially embedded in the bottom and loosen the root systems of deeply-rooted aquatic weeds. The scoop is pivotally mounted on the boom so that it can be moved by gravity to a dump position that permits gravity to act on the weed stalks and empty the scoop.
Riche, U.S. Pat. No. 4,813,377, discloses a harvester propelled forward through a body of shallow water, the water moves over the bottom of the harvester in roughly laminar flow (depth can be up to top of sides) and contacts apex of the vee gutter, and is deflected outward causing an increase in velocity to the constriction points where the ends of the vee gutter legs and curved corner plates coincide in a vertical plane. The lowered static pressure due to increased velocity at trailing edges of vee gutter legs propels the stream upward into a stagnated area behind the apex forming a vortex of counter-clockwise flow to port and clockwise flow to starboard which casts any entrained product such as crayfish into the stagnation area, thereby trapping and preventing any damage to the creatures.
Rohde, et al, U.S. Pat. No. 5,450,713 discloses a device for removing undesirable aquatic vegetation from lake bottoms. The device includes a weed trap and an elongated handle pivotally mounted thereto. The trap is formed of mesh, screen, etc. and includes at least one flat side and an open top. A cutting bar is disposed along a top edge of the flat side. A releasable latch is provided to selectively latch the handle to the trap.
Our prior art search with abstracts described above teaches several apparatus for clearing underwater brush. However, the prior art fails to teach an apparatus that is able to clamp onto and pull a shock of collected underwater weeds and, using suction, move the weeds to a collection bin afloat. The present invention fulfills these needs and provides further related advantages as described in the following summary.